As the semiconductor industry has developed and users' needs increase, electronic devices are more multi-functional, and functions of semiconductor devices that are core parts of electronic devices are increasingly diverse. However, in order for one semiconductor device to have various functions, transistors of various generations having different characteristics have to be implemented along with various functions of the semiconductor device. However, different process conditions are required for manufacturing transistors of various generations. Thus, there are many difficulties in satisfying all required characteristics of multi-functional semiconductor devices.